Flow regulating valve for magnetic particles



Oct. 22, 1968 H. G. VAN FOSSEN FLOW REGULATING VALVE FOR MAGNETICPARTICLES 2 Sheets-Sheet 1 H luv/mm? Iii-W96. Van/6x01 Filed Jan. 21,1966 M figs FLOW REGULATING VALVE FOR MAGNETIC PARTICLES Oct. 22, 1968H. G. VAN FOSSEN 2 Sheets-Sheet 2 Filed Jan.

I'A/ l/EN 7'01? Harvey G. 1622 fssarz Q i Z 513 United States Patent3,406,704 FLOW REGULATING VALVE FOR MAGNETIC PARTICLES Harvey G. VanFossen, Mishawaka, Ind., assignor to The Wheelabrator Corporation,Mishawaka, Ind., a corporation of Delaware Filed Jan. 21, 1966, Ser. No.522,318 6 Claims. (Cl. 137251) ABSTRACT OF THE DISCLOSURE A valve forregulating the flow of materials which are made up of a substantialportion of magnetic particles. The valve includes an outer member and anassembly consisting of a permanent magnet and an electrical coil, thisassembly providing a core member with a flow through passage beingprovided by spaces defined between the core member and the interior wallof the outer member. Means are provided for energizing the coil and forvarying the input to the coil to vary the influence of the magnet on theparticles and thereby regulate the flow of the material through thevalve.

This invention relates to an improved valve construction. The inventionis particularly directed to a valve construction which can beeffectively employed for modulating the flow of materials which arecomposed of a substantial portion of magnetic particles.

There are various applications which require the feeding or othermovement of materials in particle form. In certain instances, it isdesirable to provide means for regulating the flow of the particleswhereby the feeding rate can be controlled. Materials in particle formhave characteristics similar to fluids whereby valves can be employedfor regulating flow. Problems arise, however, since solid particles havea greater tendency toward clogging or otherwise disrupting valveoperations whereby high maintenance and replacement costs result. Suchditficulties arise particularly where the particles are abrasive incharacter.

This invention is particularly concerned with means for modulating theflow of particles which have magnetic characteristics. The constructionof this invention is ideally suited for use in conjunction withconstructions which employ abrasives for the cleaning of metal surfacesor the like. Various abrasives, such as shot, are magnetic in character,and it is highly desirable to provide suitable flow regulating means forsuch materials because of their abrasive characteristics. In consideringthe following description, it will be appreciated that the valvesdescribed can readily be employed for other applications, notnecessarily involving the handling of abrasive cleaning mate-rials.

It is the general object of this invention to provide an improved valveconstruction which can be employed for regulating the flow of particleswhich comprise a substantial portion of magnetic particles.

It is a more particular object of this invention to provide a valveconstruction of the type described which is characterized by a designwhich substantially reduces malfunctioning of the valve and whicheliminates the need for frequent repair and replacement.

It is a still further object of this invention to provide a valve designwhich is particularly suitable for use in conjunction with constructionswhich employ abrasive materials for use in the cleaning of metalsurfaces and the like.

These and other objects of this invention will appear hereinafter andfor purposes of illustration, but not of limitation, specificembodiments of this invention are shown in the accompanying drawings inwhich:

3,406,704 Patented Oct. 22, 1968 FIGURE 1 comprises an elevational view,partly in section, of the valve construction of this invention;

FIGURE 2 is a vertical sectional view taken about the line 2-2 of FIGURE1;

FIGURE 3 is a plan view taken about the line 33 of FIGURE 1;

FIGURE 4 is a horizontal sectional view taken about the line 44 ofFIGURE 1;

FIGURE 5 is a horizontal view taken about the line 55 of FIGURE 1;

FIGURE 6 comprises a vertical sectional view of an alternative form ofthe invention; and,

FIGURE 7 is a horizontal sectional view taken about the line 77 ofFIGURE 6.

The valve construction of this invention generally comprises a flowthrough passage defined between spacedapart wall portions of the valve.A permanent magnet is associated with the valve adjacent at least one ofthe walls whereby magnetic particles which pass through the flow throughpassage are adapted to be attracted by the magnet.

An electrical coil is also associated with the valve. This coil islocated in proximity with the magnet whereby an energization of the coilwill influence the magnetic field produced by the magnet. Means areprovided for varying the input to the coil so that correspondingvariations in the action of the magnet can be realized. The system ispreferably designed so that the effective magnetic field can vary from acondition which will prevent the passage of the abrasive material to acondition which will provide virtually free flow of the material.

The accompanying drawings illustrate a valve 10 characterized by thefeatures of this invention. This valve is adapted to be associated withan abrasive cleaning machine whereby abrasive particles can be fed intothe inlet end 12 of the valve and out of the outlet end 14. In onecontemplated application of the invention, the valves are employed forfeeding centrifugal wheels. In such an instance, the valve is mounted inassociation with the wheel housing, and the centrifugal blades engageabrasive passing through the outlet 14 for throwing of the abrasive ontoarticles to be cleaned. The valve of this invention is intended toreplace valves which have previously been employed in conjunction withsuch abrasive cleaning machines, and the mounting of the instant valvesin association with such machines is essentially the same as in the caseof previously used valves.

The valve is formed by means of a pair of outer sections 16 and 18. Therespective sections include flange members 20 defining openings 22whereby the respective sections can be mounted in a desired position.'Each of the sections also includes flange members 24. These flangemembers each define openings 26 whereby fasteners 28 can be utilized forsecuring the respective sections together.

Extending inwardly from the section 16 are a pair of wings 30 which areintegrally formed with a conically shaped cap member 32. The ends ofthese wings 30 are shaped whereby they interfit with the inclinedinterior surface 34 of section 16. A similar conically shaped cap member36 is provided with wings 38, and this arrangement is located near theoutlet end of the section 18.

Located intermediate the cap members 32 and 36 is the magnet and coilassembly of this invention. This assembly includes pole pieces 40 and 42which can be cemented or otherwise secured to the respective capmembers. Permanent magnets in the shape of discs 46 are located instacked relationship between the pole pieces 40 and 42. An electricalcoil preferably in the form of an elongated wire is wound around themagnets and pole pieces to form the cylindrical arrangement 48. Anannular passage 50 provides the flow through passage for theconstruction.

ice

-A bore 52-is defined by one of the wing members 30, and an opening 54is located at the juncture of the cylindrical members 14 and 18 forcommunication with the bore 52. Passage 56 extends from the bore 52 topassage 58 formed in the pole piece 40. This arrangement provides forthe connection of electrical leads 59 to the coil 48. Both leads 59 maypass through the described passages.

In the operation of the described construction, material is passed intothe inlet 12 and through the passage 50. If the valve is to provide foressentially free flow of the particles, the electrical coil 48 isenergized to the extent necessary for offsetting the influence of thepermanent magnets 46. With this arrangement, substantially free flow ofthe particles can be accomplished.

When the flow of particles is to be retarded, the energization is variedby the necessary amount to achieve a reduction in flow rate. Obviously,the flow of particles can be substantially stopped by de-energizing theelectrical coil provided permanent magnets of the necessary strength areemployed. It will be appreciated that stopping of the flow may not benecessary for some applications.

' The valve construction described can be utilized in conjunction withmaterials which comprise a substantial portion of particles adapted tobe attracted by magnetic forces. The invention contemplates the handlingof mixtures of magnetic and nonmagnetic materials, particularly Wherethe dominant portion of the materials is magnetic and will influence theflow rate of all the materials.

The valve will function even when the major portion of the material isnon-magnetic and a minor portion is magnetic, In such case, it will havea slightly slower response to changes in magnetic field. For example, ifa mixture of 40 percent magnetic steel shot and 60 percent sand, byvolume, was passing through the valve at full flow rate, the coil couldbe partially de-energized such that the permanent magnets will attractthe magnetic particles in the mixture and restrict the opening in thevalve, thus reducing the flow of both magnetic and non-magnetic materialthrough the valve. When the coil was fully deenergized, still moremagnetic particles would be attracted to the permanent magnet with thesand momentarily passing through the valve, but with more oncomingmagnetic particles being quickly attracted by the magnet, almostinstantaneous blocking of the entire passage within the valve by themagnetic particles will result and thus prevent flow of the non-magneticparticles through the valve.

One contemplated application of the invention comprises the use of thedescribed constructions as abrasive control valves for a machine such asdescribed in United States Patent No. 3,188,776. In such constructions,two or more multiple centrifugal wheels operate in tandem, and in someinstances, shot is used in one section of the construction and grit inanother. Depending upon the type of material to be cleaned, differentamounts of shot and grit are employed for providing optimum cleaning.With the valves of this invention, the abrasive flow for any givensection can be automatically regulated depending upon the grade of steelbeing cleaned. Variations can also easily be made once an operation hasbegun. The use of these valves is quite important from the standpoint ofinitial machine design since the machine can be provided with enoughwheels and enough horsepower in each section to meet all possiblevariations. The given sections can then be readily operated at desiredspeeds for a given job.

In some instances, wide strip is cleaned by applying abrasive from threeor more wheels which are located in side-by-side relationship forcovering the entire width of the steel. Since such strips may vary indegree of scale thickness or scale toughness at different locations,such as the edges as contrasted to the middle, it is highly desirable tohave reliable valve means for applying abrasives at different rates todifferent areas of the steel surface. The valve means are also ideallysuited for situations wherein the operation of a particular line is cutback without being completely stopped. For example, there may beinsulficient steel for cleaning over a given period of time; however, asteady flow may be desired and, therefore, temporary operation at halfline speed and at half the rate of abrasive flow is undertaken. Thevalves of this invention readily permit such an arrangement.

The electrical coil is preferably energized from a DC source. In such aninstance, modulation of the flow can be efiiciently accomplished since aplot of voltage against abrasive flow becomes practically a straightline function:

In one particular form of the invention, seven permanent magnets formedof Indox 5 and magnetized to full strength are stacked. The diameter ofthe magnets was 2.38 inches, the total length of the stack was2.506inches with an air gap 50 between the magnets and the housing 18 ofone inch. An electrical coil formed of No. 23 gauge ML copper wire witha wire coating epoxy capable of withstanding temperatures to 357 F. wasassociated with the magnets. The leads were 12 inches minimum length andof ZO-gauge Teflon type E insulated wire. The coil power rating was 175watts plus or minus 10 percent with a coil resistance of 45 ohms.

The pole piece extensions 40 and 42 serve a very useful purpose in theconstruction. These extensions add approximately 1% inches to each endof the magnets, and they permit the use of a smaller diameter coil forpurposes of neutralizing the magnetization of the permanent magnets. Theuse of a larger coil compressed into the length of the permanent magnetswould require a substantially greater voltage for achieving the sameresults, and excessive heat would be developed in the coils which couldcause them to burn out.

The conically shaped cap members 32 and 36 also serve a very usefulpurpose in the construction. They streamline the abrasive flow throughthe valve and most important, they can be made of abrasion-resistant,nonmagnetic and good heat conducting material. Preferably, the capmembers comprise a cast mixture of fine sized silicon carbide and epoxycement so that they protect the pole piece extensions 40 and 42 fromwear, and they dissipate heat away from the electric coils bytransferring the heat to the abrasiv flowing over the caps.

The construction shown in FIGURES 6 and 7 comprises an alternative formof the invention. This arrangement includes a cylindrical section 70defining a flow through passage 72. Upper and lower flanges 74 can beutilized for securing the cylinder 70 in the manner previouslydescribed.

Pole pieces 76 extend into the flow through passage through openings 78in the walls of the cylinder 70. The pole pieces are interconnected bymeans of a bar 80, and this bar comprises a permanent magnet whereby thepole pieces will attract abrasive particles in accordance with theprevious description. The cylinder 70 is preferably formed of anon-magnetic stainless steel whereby it will have no direct influence onthe magnetic characteristics of the system.

An electromagnetic coil 82 is wrapped around the permanent magnet 80,and the electrical leads 84 provide for energization of the coil. Thisalternative arrangement is, thus, adapted to operate in a manner similarto the above described arrangement. The coil 82 will influence thepermanent magnet characteristics to the extent that the pole pieces 76can act as valve means for regulating the flow of abrasive particlesthrough the cylinder 70.

This alternative arrangement is particularly useful where hot particlesare passing through the valve. Heat build-up around the electromagneticcoil can be avoided when this coil is located outside the passage. Hotsteel abrasives are handled, for example, during their manufacture,where it is desired to take hot abrasive after they have passed througha drier and control the flow over airwash separators to remove slag andother debris prior to heat treating. The alternative form of thisinvention finds use in such systems as well as in other systemsinvolving a variety of different operations.

A silicon control DC rectifier varying the DC voltage between and 95volts is preferably employed with constructions of the type describedabove. This arrangement or any conventional rectifier is utilized inconjunction with an ordinary 110 volt AC line current. With anarrangement of this type, steel shot will flow when the voltage exceedsabout volts and will increase to a maximum at a voltage of about 95volts with the magnetization being sufiiciently neutralized at thispoint so that it no longer retards the flow of magnetic particles.

The following table provides an illustration of typical flow rates in asystem of the type described:

Volts DC Pounds per minute abrasive flow to coil round steel shot 0.01to 0.02" dia. 20 0 792 1515 1962 2610 3129 3651 4011 4077 The valveconstructions of this invention are characterized by various advantageswhen compared with conventional valves employed for similar purposes.The constructions do not utilize moving parts and, therefore, bits ofabrasive will not cause binding or malfunctions in the valves. Thearrangements are compact whereby they can be readily incorporated invarious machines. The size and elimination of moving parts makes thearrangements extremely inexpensive and easy to install.

A more uniform and accurate regulation or proportioning of the abrasiveflow is possible with this valve than with conventional abrasive flowvalves. Since the abrasive flow can be stopped when the current is shutoff, the valve constructions are essentially fail safe. Thus, anyaccidental loss in line current will shut off abrasive flow.

Th valve constructions do not develop magnetic force outside of thevalve housing and, therefore, abrasive dust is not attracted to thevalve area. It is also to be noted that the abrasives flowing throughthe valve do not retain any significant residual magnetism. If any smallamount of magnetism is picked up, it is lost during impact after theabrasive is thrown by the centrifugal wheel against the work.

It will be appreciated that various changes and modifications may bemade in the construction of this invention which provide thecharacteristics of this invention without departing from the spiritthereof particularly as defined in the following claims.

That which is claimed is:

1. A valve for use in the handling of materials which are in particleform and which comprise a substantial portion of magnetic particles,said valve comprising an outer member defining a flow-through passage, apermanent magnet associated with said valve adjacent at least one wallthereof, said magnet being adapted to attract said particles and tothereby impede movement of the particles through the passage, anelectrical coil, said magnet and said coil comprising an assemblyforming a core member disposed within the confines of said outer memberwith said passage comprising a space defined between said core memberand said outer member, means for energizing said coil, and means forvarying the input to said coil for thereby varying the influence of saidmagnet on said particles.

2. A valve in accordance with claim 1 wherein the assembly comprisingsaid core member includes said magnet in an internal portion with saidcoil surrounding said magnet.

3. A valve in accordance with claim 2 including cap members covering theends of said core member and wings associated with said cap membersextending outwardly toward the interior walls of said outer member, saidwings interconnecting said core member and said walls for supporting thecore member within the outer member.

4. A valve in accordance with claim 3 including a bore defined in atleast one of said wings, an opening in said outer member communicatingsaid bore with the exterior of said valve, and leads from said coilextending through said bore and out of said opening to provid anelectrical connection for said coil.

5. A valve in accordance with claim 2 including pole piece extensionslocated at the opposite ends of said magnet, and wherein said coilextends beyond said magnet and over said extensions.

6. A valve in accordance with claim 2 wherein said magnet is formed of aplurality of separate discs arranged in stacked relationship, andwherein said coil comprises a continuous length of wire wound in aplurality of turns around said stacked discs.

References Cited UNITED STATES PATENTS 1,747,044 2/ 1930 Bainbridge137251 X 2,154,843 4/1939 Hammell 519 2,160,697 5/1939 Hamren 5192,263,321 11/1941 Unger 5l9 2,505,049 4/1950 Keller 302-47 2,651,2589/1953 Pierce 103--1 2,670,749 3/ 1954 Germer 1371 2,820,471 1/1958Crowell l37251 3,010,471 11/1961 Gross 137-251 3,188,776 6/1965 Dill51320 LESTER M. SWINGLE, Primary Examiner.

